RS Aggarwal Solutions Class 8 Chapter-20 Volume and Surface Area of Solids (Ex 20B) Exercise 20.2

Class 8 RS Aggarwal Exercise 20B free PDF solutions are available for the students to avoid the last-minute rush in solving a particular problem. Vedantu expert teachers are always ready to help students with each question with the respected explanation to each. Hence clarifying the doubts is not a big task today. It could be tough for students to prepare and solve each question of Mathematics before the exam. However, if proper answers are available to them with an explanation, it does not seem much difficult for them to crack it. RS Aggarwal is the best book for reference. Also, it is good if students brush up their skills for preparing well in future considerations. Students will get proper RS Aggarwal Class 8 20B solutions so that they do not need any extra help in future to solve them. It is better to clarify your concepts and revise the entire syllabus before the exam. That’s why Vedantu provides readymade free PDF for RS Aggarwal Solutions Class 8 Ex 20 B. 

RS Aggarwal Class 8 Chapter 20 Exercise 20B Solutions

The concept of volume and surface area is applicable to 3D objects and geometrical figures. We define the surface area as the region occupied by an object. However, the volume is given by the space that an object occupies. 

The basic 3D shapes in geometry for which we calculate surface area and volume are cubes, sphere, cuboid, cone, and cylinder. However, you can form other shapes by combining two or three of them. Thus, you have to find the total surface area and volume occupied by them. However, these examples become quite complex. Thus these are usually included in the last exercise of Chapter 20. 

Some basic problems that we generally come across with volume and surface areas are listed below:

Question: Suppose you are given two diagonals of a rhombus as 40 cm and 30 cm. You need to find the length for its sides. 

Solution: We know that diagonals of a rhombus bisect each other. Thus their half is given by 20 and 15 cm each. 

Therefore, the side will be given by 

= √225 + 400

= √625

= 25 cm

All the sides of a rhombus are equal. Hence the length of each side is 25 cm. 

Question: What is the total surface area for a sphere and a hemisphere?

Solution: The total surface area for a sphere is given as 4Πr2

Hence the total surface area for a hemisphere is given by half of the sphere surface area in addition to the surface area of the base. 

= 2Πr2 + Πr2

Whether it is about solving NCERT questions or moving to the next level questions, RS Aggarwal solutions could be the best preference. The subject of the surface area of solids is the most important concept with real-life applications. Hence students must make sure to master their concepts in it. RS Aggarwal Solutions Class 8 Exercise 20B could help them even to prepare for future knowledge in competitive exams. Vedantu experts have provided these solutions for the students to have a better understanding. 

Benefits of RS Aggarwal Class 8 Exercise 20 B Solutions

It could be very challenging for most of the students to prepare well before exams. However, if the concepts are clear before time, it is easy to master the exams. RS Aggarwal Class 8 Chapter 20B Exercise is an important concept of Mathematics that students need to clear well. The chapter has high weightage in the examination. Thus, they need to prepare accordingly. Some listed benefits of having RS Aggarwal Class 8 Exercise 20B solutions are:

• Students can learn the way to attempt and score marks for each step performed.

• Students will get familiar with the new level questions that are expected to come in the exams apart from NCERT ones.

• Regular practice of the questions after finding a perfect solution can let students master their skills. Thus it makes them confident to solve any similar problems in future. 

Important terms related to Class 8 Chapter 20

Students need to understand the different terms related to chapter 20 of class 8 maths. They must understand the different terms such as surface area, volume, curved surface area, and lateral surface area of a solid figure to understand this chapter properly.

The surface area of a solid is the sum of areas of all the faces of the given solid.

The volume of a solid is the capacity of a given solid or the inside space of the figure.

The curved surface area of a solid is the sum of all the curved surfaces of a given solid shape.

The lateral surface area of a solid is the area of the sides around it excluding the top and bottom faces of the figure. 

Formulas:

Some important formulas related to the Class 8  maths chapter 20 are given here:

The surface area of a cube: All sides of a cube are equal and therefore the surface area of a cube is equal to 6l² if l is the measure of each side of a cube.

The surface area of a cuboid is given by formula 2 (bh + hl + lb) where l is the length, b is the breadth, and h is the height of the cuboid. 

The volume of a cuboid is given by the formula lxbxh where l is the length, b is the breadth, and h is the height.

The volume of a cube is given by the formula l3 because all sides of a cube are equal thus lxlxl= l3

The surface area of a cylinder is given by the formula 2xπ x r(r + h) where r is the radius of a cylinder and h is the height. 

The volume of a cylinder is given by the formula π x r(r + h) = π r2h where r is the radius and h is the height of the cylinder.

The lateral or curved surface area of a cube is given by the formula 4l2 where l is the length of the cube.

The lateral or curved surface area of a cuboid is given by the formula 2h (l+b) where l is the length, b is the breadth, and h is the height of the cuboid.

The lateral or curved surface area of a cylinder is given by the formula 2πrh where r is the radius of its circular base and h is the height of the cylinder.